
import numpy as np
import matplotlib.pyplot as plt 
def mandelbrot(h,w,maxit=20):
    y,x = np.ogrid[-1.4:1.4:h*1j,-2:0.8:w*1j]
    c = x+y*1j
    z = c 
    divtime = maxit + np.zeros(z.shape,dtype=int)
    for i in range(maxit):
        z = z**2 +c
        diverge = z*np.conj(z) > 2**2
        div_now = diverge & (divtime==maxit)
        divtime[div_now] = i 
        z[diverge] = 2 
    return divtime
 
plt.imshow(mandelbrot(400,400))
plt.show()